The invention relates to an apparatus for producing a homogeneous flexible layer of material from blocks of highly consistent material, such as butter or margarine.
The layer consisting of butter or margarine obtained from such apparatus is intended to be put on top of a layer of dough or is to be laminated between several other layers.
Until now such a layer of butter or margarine was obtained by means of an apparatus of a type of the well-known mincer, which minces blocks of input raw material and conveys the minced material by an endless conveyor screw to an outlet aperture.
However, an important drawback of said known apparatus is that it is very difficult to obtain and to maintain an endless homogenous output layer with a thickness or vertical cross-section which is of uniform dimension. Other drawbacks of said known apparatus are, that it is very difficult to clean, which is an important item within food processing, and that it consumes too much drive power.
From U.S. Pat. No. 3,205,838 (Frobeen) an extrusion press for processing fats and dough is known comprising a pair of rotatably driven rotors, arranged in parallel in a horizontal plane, each rotor being provided with axially arranged slots in their outer surface, each of said slots having a blade which is controlled slideably in a radially direction, the blades being guided such that they project out of said rotors in an upper quarter region, while contacting or almost contacting the respective similar projected blade of the opposite rotor and, while turned down subsequently by continued rotation of the rotors, they are retracted subsequently and guided along a respective one of a pair of scraper elements, which form the upper border to a pressure room and which bear close against said rotors.
With the Frobeen apparatus the raw input material which, significantly has a low consistency and is fed into a hopper, which is arranged above said rotors, so that the raw input material is enabled to thus flow by gravity between the upper, projecting blades of said rotors and can thus be conveyed through the intermediate region between said rotors into said pressure room.
It is the object of the invention, on the contrary, to provide an apparatus for producing a homogeneous flexible layer of material from blocks of highly consistent material, such as butter or margarine, which apparatus does not have the drawbacks of said known apparatus.
Therefore, according to the invention, an apparatus is provided for producing a homogeneous flexible layer of flexible material from blocks of a highly consistent material, such as butter or margarine comprising: an upper input portion having a pair of substantially vertical, parallel extending sidewalls the edges of each defining the border of an upper input opening and of a lower output opening of said input portion, said sidewalls being arranged such as to guide said blocks of highly consistent material in close relationship in a vertical direction, which blocks are to be input into the upper opening of said input portion; a central portion comprising a housing having an upper inlet section and a lower outlet section, the inlet section being arranged opposite to and aligned with the output opening of said input portion, a pair of elongate rotors which are disposed in parallel in a substantially horizontal plane inside said housing, the rotors defining an intermediate conveying section in between, the rotors being rotatably driven by means of a drive mechanism such that the left rotor of said rotors is driven clockwise and the other rotor is driven counterclockwise, the distance between the axes of said rotors being greater than the distance between said sidewalls of the input portion at the output opening thereof, each rotor defining a number of rectangular slots which are formed in parallel to the axes of said rotors on the outer circumference thereof; each slot being provided with a blade, which is substantially radially displaceable with respect to the rotor, each blade being provided with guide elements at the most outer ends thereon which elements, during rotation of the rotor, are guided inside a pair of grooves, said grooves being formed opposite the respective ends of each of said rotors in the side walls of the housing, each such groove having a loop shape extending gradually in such a manner that the blades are retracted completely inside the corresponding slots when brought into said outlet section and the blades are extended elsewhere such and the rotors being disposed and driven such, that the blades of the opposed rotors mesh with each other and are close to the opposite rotor in said conveying section, while the blades can scrape slices of material from said blocks, which are to be placed on top of said rotors, and the blades convey said scraped material into said outlet section; and a lower output portion having two sidewalls which converge such as to define a rectangular input opening opposite to and aligned with the output section of said central portion and a smaller lower rectangular output opening, the upper edge of each of said side walls of said lower portion being provided with a scraper element which bears against the outer surface of a respective one of said rotors, thus said layer can be output homogenous from said apparatus through said output opening of said lower output portion.
With the apparatus of the invention the upper, projecting blades of each of said rotors grasp into the bottom parts of said blocks, so that the blades cut slices from said bottom parts, which are subsequently conveyed through the intermediate region between said rotors into the lower output portion. Because the blades of different rotors intermesh always in said intermediate region and bear against the respective opposite rotor, a pressure on said material to be treated in the output portion is built up, so that the layer thus obtained by extrusion from said output portion will be continuously homogenous and will have a thickness or vertical cross-section which is of uniform dimension. It is important therewith that the distance between the side walls of the input portion which are parallel to the rotor axis is less than the distance between said rotor axis.
Such an action is not possible with the Frobeen apparatus, because the many blades thereof cannot grasp engage or scrape into bottom parts of blocks of highly consistent material placed on top of such rotors, the blades of Frobeen more likely supporting said blocks than to cut them. This unique effect is even emphasized because a pair of upper side walls, of the invention wherein the lower edges are parallel to the rotors, converts downwardly to an output opening of said hopper whereby the dimension perpendicular to the rotor axis is greater than the distance between the axis of said rotors.
The apparatus according to the invention has a very high efficiency, and can be easily cleaned after use. Power consumption is relatively low.